The complex mechanisms of cell-cell interaction, as mediated by intercellular junctions, are now being understood at the molecular level. With this understanding comes the recognition of how cells utilize junctions to define physiological compartments within organisms, interlock their intracellular skeletal and motility systems, and exchange a variety of intercellular signals. Moreover, the pathophysiology of various diseases involves mutations in, immune responses to and misregulation and junctional components. Recent studies have 1) revealed new functions for junctional proteins in tissue development and homeostasis, 2) begun to dissect interactions that occur between these proteins and 3) examined the effects of mutation or disruption of junctional elements on normal cellular physiology. Key remaining questions include understanding how different intercellular junctions interact via intracellular signaling systems and how their structural and signaling functions are integrated at the molecular level. This meeting will bring together leading investigators in these areas of research. The key and unique feature of this meeting is that it is multidisciplinary. Rather than focus on a particular intercellular junction, as occurs at most specialty meetings, a group of principal investigators, postdoctoral fellows, and graduate students will be assembled to exchange information on distinct but clearly related areas. This approach, successfully introduced at a Keystone Symposium in 1996, will permit participants, particularly junior scientists, the opportunity to view the field of cell-cell interactions in a broad and encompassing context, providing not only a definition of the common ground, but more importantly a comprehensive perspective in which to frame future investigations.